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  • vb.net亚博足球娱乐场注册--任意三数字加yabo.com直达官网之C#和VB.net语法对比图

  • 2019-06-19 22:12 来源:未知

Comments
?
VB.NET

?

'Single line only
Rem Single line only
?
?C#

// Single line
/* Multiple
line */
/// XML comments on single line
/** XML comments on multiple lines */
?
Data Types
?
VB.NET

?

'Value Types
Boolean
Byte
Char (example: "A")
Short, Integer, Long
Single, Double
Decimal
Date


'Reference Types
Object
String

?

Dim x As Integer
System.Console.WriteLine(x.GetType())
System.Console.WriteLine(TypeName(x))


'Type conversion
Dim d As Single = 3.5
Dim i As Integer = CType (d, Integer)
i = CInt (d)
i = Int(d)
?
?C#

?

//Value Types
bool
byte, sbyte
char (example: 'A')
short, ushort, int, uint, long, ulong
float, double
decimal
DateTime


//Reference Types
object
string

?

int x;
Console.WriteLine(x.GetType())
Console.WriteLine(typeof(int))


//Type conversion
float d = 3.5;
int i = (int) d
?
?
Constants
?
VB.NET

Const MAX_AUTHORS As Integer = 25
ReadOnly MIN_RANK As Single = 5.00
?C#

const int MAX_AUTHORS = 25;
readonly float MIN_RANKING = 5.00;
?
Enumerations
?
VB.NET

Enum Action
? Start
? 'Stop is a reserved word
[Stop]
? Rewind
? Forward
End Enum

Enum Status
?? Flunk = 50
?? Pass = 70
?? Excel = 90
End Enum

Dim a As Action = Action.Stop?
If a <> Action.Start Then _
'Prints "Stop is 1"?
?? System.Console.WriteLine(a.ToString & " is " & a)

'Prints 70
System.Console.WriteLine(Status.Pass)
'Prints Pass
System.Console.WriteLine(Status.Pass.ToString())
?C#

enum Action {Start, Stop, Rewind, Forward};
enum Status {Flunk = 50, Pass = 70, Excel = 90};

?

?

?

?

?

Action a = Action.Stop;
if (a != Action.Start)
//Prints "Stop is 1"
? System.Console.WriteLine(a + " is " + (int) a);

// Prints 70
System.Console.WriteLine((int) Status.Pass);?
// Prints Pass
System.Console.WriteLine(Status.Pass);
?
Operators
?
VB.NET

?

'Comparison
=? ? <=? >=? <>


'Arithmetic
+? -? *? /
Mod
? (integer division)
^? (raise to a power)


'Assignment
=? +=? -=? *=? /=? =? ^=? <<=? >>=? &=


'Bitwise
And? AndAlso? Or? OrElse? Not? <>


'Logical
And? AndAlso? Or? OrElse? Not


'String Concatenation
&?
?
?C#

?

//Comparison
==? ? <=? >=? !=


//Arithmetic
+? -? *? /
%? (mod)
/? (integer division if both operands are ints)
Math.Pow(x, y)


//Assignment
=? +=? -=? *=? /=?? %=? &=? |=? ^=? <<=? >>=? ++? --


//Bitwise
&? |? ^?? ~? <>


//Logical
&&? ||?? !


//String Concatenation
+
?
?
Choices
?
VB.NET

?

greeting = IIf(age < 20, "What's up?", "Hello")


'One line doesn't require "End If", no "Else"
If language = "VB.NET" Then langType = "verbose"


'Use: to put two commands on same line
If x <> 100 And y < 5 Then x *= 5 : y *= 2??


'Preferred
If x <> 100 And y < 5 Then
? x *= 5
? y *= 2
End If

?


'or to break up any long single command use _
If henYouHaveAReally < longLine And _?
itNeedsToBeBrokenInto2?? > Lines? Then _
? UseTheUnderscore(charToBreakItUp)


If x > 5 Then
? x *= y?
ElseIf x = 5 Then
? x += y?
ElseIf x < 10 Then
? x -= y
Else
? x /= y
End If


'Must be a primitive data type
Select Case color???
? Case "black", "red"
??? r += 1
? Case "blue"
??? b += 1
? Case "green"
??? g += 1
? Case Else
??? other += 1
End Select
?
?C#

?

greeting = age < 20 ? "What's up?" : "Hello";

?

?

?

?

?

if (x != 100 && y < 5)
{
? // Multiple statements must be enclosed in {}
? x *= 5;
? y *= 2;
}

?

?

?


if (x > 5)?
? x *= y;?
else if (x == 5)?
? x += y;?
else if (x < 10)?
? x -= y;?
else?
? x /= y;

?

//Must be integer or string
switch (color)
{
? case "black":
? case "red":??? r++;
?? break;
? case "blue"
?? break;
? case "green": g++;??
?? break;
? default:??? other++;
?? break;
}
?
?
Loops
?
VB.NET

?

'Pre-test Loops:
While c < 10
? c += 1
End While Do Until c = 10
? c += 1
Loop


'Post-test Loop:
Do While c < 10
? c += 1
Loop


For c = 2 To 10 Step 2
? System.Console.WriteLine(c)
Next

?

'Array or collection looping
Dim names As String() = {"Steven", "SuOk", "Sarah"}
For Each s As String In names
? System.Console.WriteLine(s)
Next
?
?C#

//Pre-test Loops: while (i < 10)
? i++;
for (i = 2; i < = 10; i += 2)
? System.Console.WriteLine(i);

?

?


//Post-test Loop:
do
? i++;
while (i < 10);

?

?

?


// Array or collection looping
string[] names = {"Steven", "SuOk", "Sarah"};
foreach (string s in names)
? System.Console.WriteLine(s);
?
?
Arrays
?
VB.NET

?

Dim nums() As Integer = {1, 2, 3}
For i As Integer = 0 To nums.Length - 1?
? Console.WriteLine(nums(i))?
Next

'4 is the index of the last element, so it holds 5 elements
Dim names(4) As String
names(0) = "Steven"
'Throws System.IndexOutOfRangeException
names(5) = "Sarah"


'Resize the array, keeping the existing
'values (Preserve is optional)
ReDim Preserve names(6)

?

?

Dim twoD(rows-1, cols-1) As Single?
twoD(2, 0) = 4.5


Dim jagged()() As Integer = { _
? New Integer(4) {}, New Integer(1) {}, New Integer(2) {} }
jagged(0)(4) = 5
?
?C#

?

int[] nums = {1, 2, 3};
for (int i = 0; i < nums.Length; i++)
? Console.WriteLine(nums[i]);


// 5 is the size of the array
string[] names = new string[5];
names[0] = "Steven";
// Throws System.IndexOutOfRangeException
names[5] = "Sarah"


// C# can't dynamically resize an array.
//Just copy into new array.
string[] names2 = new string[7];
// or names.CopyTo(names2, 0);
Array.Copy(names, names2, names.Length);

?

float[,] twoD = new float[rows, cols];
twoD[2,0] = 4.5;


int[][] jagged = new int[3][] {
? new int[5], new int[2], new int[3] };
jagged[0][4] = 5;
?
?
Functions
?
VB.NET

?

'Pass by value (in, default), reference
'(in/out), and reference (out)
Sub TestFunc(ByVal x As Integer, ByRef y As Integer,
ByRef z As Integer)
? x += 1
? y += 1
? z = 5
End Sub


'c set to zero by default

Dim a = 1, b = 1, c As Integer
TestFunc(a, b, c)
System.Console.WriteLine("{0} {1} {2}", a, b, c) '1 2 5


'Accept variable number of arguments
Function Sum(ByVal ParamArray nums As Integer()) As Integer
? Sum = 0
? For Each i As Integer In nums
??? Sum += i
? Next
End Function 'Or use a Return statement like C#

Dim total As Integer = Sum(4, 3, 2, 1) 'returns 10


'Optional parameters must be listed last
'and must have a default value
Sub SayHello(ByVal name As String,
Optional ByVal prefix As String = "")
? System.Console.WriteLine("Greetings, " & prefix
& " " & name)
End Sub


SayHello("Steven", "Dr.")
SayHello("SuOk")


?
?C#

// Pass by value (in, default), reference
//(in/out), and reference (out)
void TestFunc(int x, ref int y, out int z) {
? x++;
? y++;
? z = 5;
}

?


int a = 1, b = 1, c; // c doesn't need initializing
TestFunc(a, ref b, out c);
System.Console.WriteLine("{0} {1} {2}", a, b, c); // 1 2 5


// Accept variable number of arguments
int Sum(params int[] nums) {
? int sum = 0;
? foreach (int i in nums)
??? sum += i;
? return sum;
}


int total = Sum(4, 3, 2, 1); // returns 10


/* C# doesn't support optional arguments/parameters.
Just create two different versions of the same function. */
void SayHello(string name, string prefix) {
? System.Console.WriteLine("Greetings, "? + prefix + " " + name);
}

void SayHello(string name) {
? SayHello(name, "");
}
?
?
Exception Handling
?
VB.NET

?

'Deprecated unstructured error handling
On Error GoTo MyErrorHandler
...
MyErrorHandler: System.Console.WriteLine(Err.Description)

Dim ex As New Exception("Something has really gone wrong.")
Throw ex


Try
? y = 0
? x = 10 / y
Catch ex As Exception When y = 0 'Argument and When is optional
? System.Console.WriteLine(ex.Message)?
Finally
? DoSomething()?
End Try
?
?C#

?

?

?

Exception up = new Exception("Something is really wrong.");?
throw up; // ha ha


try{
? y = 0;
? x = 10 / y;
}
catch (Exception ex) { //Argument is optional, no "When" keyword
? Console.WriteLine(ex.Message);
}
finally{
? // Do something
}
?
?
Namespaces
?
VB.NET

?

Namespace ASPAlliance.DotNet.Community
? ...
End Namespace


'or


Namespace ASPAlliance?
? Namespace DotNet
??? Namespace Community
????? ...
??? End Namespace
? End Namespace
End Namespace


Imports ASPAlliance.DotNet.Community
?
?C#

?

namespace ASPAlliance.DotNet.Community {
? ...
}


// or


namespace ASPAlliance {
? namespace DotNet {
??? namespace Community {
????? ...
??? }
? }
}


using ASPAlliance.DotNet.Community;
?
?
Classes / Interfaces
?
VB.NET

?

'Accessibility keywords
Public
Private
Friend
Protected
Protected Friend
Shared


'Inheritance
Class Articles
? Inherits Authors
? ...
End Class


'Interface definition
Interface IArticle?
? ...
End Interface


'Extending an interface
Interface IArticle
? Inherits IAuthor
? ...
End Interface


'Interface implementation
Class PublicationDate
? Implements IArticle, IRating
?? ...
End Class
?
?C#

?

//Accessibility keywords
public
private
internal
protected
protected internal
static


//Inheritance
class Articles: Authors {
? ...
}

?

//Interface definition
interface IArticle {
? ...
}


//Extending an interface
interface IArticle: IAuthor {
? ...
}

?

//Interface implementation
class PublicationDate: IArticle, IRating {
?? ...
}
?
?
Constructors / Destructors
?
VB.NET

Class TopAuthor
? Private _topAuthor As Integer

? Public Sub New()
??? _topAuthor = 0
? End Sub

? Public Sub New(ByVal topAuthor As Integer)
??? Me._topAuthor = topAuthor
? End Sub

? Protected Overrides Sub Finalize()
?? 'Desctructor code to free unmanaged resources
??? MyBase.Finalize()?
? End Sub
End Class
?C#

?

class TopAuthor {
? private int _topAuthor;

? public TopAuthor() {
???? _topAuthor = 0;
? }

? public TopAuthor(int topAuthor) {
??? this._topAuthor= topAuthor
? }

? ~TopAuthor() {
??? // Destructor code to free unmanaged resources.
??? // Implicitly creates a Finalize method
? }
}
?
?
Objects
?
VB.NET

?

Dim author As TopAuthor = New TopAuthor
With author
? .Name = "Steven"
? .AuthorRanking = 3
End With

author.Rank("Scott")
author.Demote() 'Calling Shared method
'or
TopAuthor.Rank()


Dim author2 As TopAuthor = author 'Both refer to same object
author2.Name = "Joe"
System.Console.WriteLine(author2.Name) 'Prints Joe


author = Nothing 'Free the object


If author Is Nothing Then _
? author = New TopAuthor


Dim obj As Object = New TopAuthor
If TypeOf obj Is TopAuthor Then _
? System.Console.WriteLine("Is a TopAuthor object.")
?
?C#

?

TopAuthor author = new TopAuthor();

//No "With" construct
author.Name = "Steven";
author.AuthorRanking = 3;


author.Rank("Scott");
TopAuthor.Demote() //Calling static method

?


TopAuthor author2 = author //Both refer to same object
author2.Name = "Joe";
System.Console.WriteLine(author2.Name) //Prints Joe


author = null //Free the object


if (author == null)
? author = new TopAuthor();


Object obj = new TopAuthor();?
if (obj is TopAuthor)
? SystConsole.WriteLine("Is a TopAuthor object.");
?
?
Structs
?
VB.NET

?

Structure AuthorRecord
? Public name As String
? Public rank As Single

? Public Sub New(ByVal name As String, ByVal rank As Single)?
??? Me.name = name
??? Me.rank = rank
? End Sub
End Structure


Dim author As AuthorRecord = New AuthorRecord("Steven", 8.8)
Dim author2 As AuthorRecord = author

author2.name = "Scott"
System.Console.WriteLine(author.name) 'Prints Steven
System.Console.WriteLine(author2.name) 'Prints Scott
?
?C#

struct AuthorRecord {
? public string name;
? public float rank;

? public AuthorRecord(string name, float rank) {
??? this.name = name;
??? this.rank = rank;
? }
}

?

AuthorRecord author = new AuthorRecord("Steven", 8.8);
AuthorRecord author2 = author

author.name = "Scott";
SystemConsole.WriteLine(author.name); //Prints Steven
System.Console.WriteLine(author2.name); //Prints Scott
?
?
Properties
?
VB.NET

?

Private _size As Integer

Public Property Size() As Integer
? Get
??? Return _size
? End Get
? Set (ByVal Value As Integer)
??? If Value < 0 Then
????? _size = 0
??? Else
????? _size = Value
??? End If
? End Set
End Property


foo.Size += 1
?
?C#

private int _size;

public int Size {
? get {
??? return _size;
? }
? set {
??? if (value < 0)
????? _size = 0;
??? else
????? _size = value;
? }
}

?

foo.Size++;
?
?
Delegates / Events
?
VB.NET

?

Delegate Sub MsgArrivedEventHandler(ByVal message
As String)


Event MsgArrivedEvent As MsgArrivedEventHandler


'or to define an event which declares a
'delegate implicitly
Event MsgArrivedEvent(ByVal message As String)


AddHandler MsgArrivedEvent, AddressOf My_MsgArrivedCallback
'Won't throw an exception if obj is Nothing
RaiseEvent MsgArrivedEvent("Test message")
RemoveHandler MsgArrivedEvent, AddressOf My_MsgArrivedCallback

?

Imports System.Windows.Forms


'WithEvents can't be used on local variable
Dim WithEvents MyButton As Button
MyButton = New Button


Private Sub MyButton_Click(ByVal sender As System.Object, _
? ByVal e As System.EventArgs) Handles MyButton.Click
? MessageBox.Show(Me, "Button was clicked", "Info", _
??? MessageBoxButtons.OK, MessageBoxIcon.Information)
End Sub
?
?C#

?

delegate void MsgArrivedEventHandler(string message);


event MsgArrivedEventHandler MsgArrivedEvent;


//Delegates must be used with events in C#


MsgArrivedEvent += new MsgArrivedEventHandler
? (My_MsgArrivedEventCallback);
//Throws exception if obj is null
MsgArrivedEvent("Test message");
MsgArrivedEvent -= new MsgArrivedEventHandler
? (My_MsgArrivedEventCallback);

?

using System.Windows.Forms;


Button MyButton = new Button();
MyButton.Click += new System.EventHandler(MyButton_Click);


private void MyButton_Click(object sender,??? System.EventArgs e) {
? MessageBox.Show(this, "Button was clicked", "Info",
??? MessageBoxButtons.OK, MessageBoxIcon.Information);
}
?
?
Console I/O
?
VB.NET

?

'Special character constants
vbCrLf, vbCr, vbLf, vbNewLine
vbNullString
vbTab
vbBack
vbFormFeed
vbVerticalTab
""
Chr(65) 'Returns 'A'


System.Console.Write("What's your name? ")
Dim name As String = System.Console.ReadLine()
System.Console.Write("How old are you? ")
Dim age As Integer = Val(System.Console.ReadLine())
System.Console.WriteLine("{0} is {1} years old.", name, age)
'or
System.Console.WriteLine(name & " is " & age & " years old.")

Dim c As Integer
c = System.Console.Read() 'Read single char
System.Console.WriteLine(c) 'Prints 65 if user enters "A"
?
?C#

?

//Escape sequences
n, r
t

?


Convert.ToChar(65) //Returns 'A' - equivalent to Chr(num) in VB
// or
(char) 65


System.Console.Write("What's your name? ");
string name = SYstem.Console.ReadLine();
System.Console.Write("How old are you? ");
int age = Convert.ToInt32(System.Console.ReadLine());
System.Console.WriteLine("{0} is {1} years old.",? name, age);
//or
System.Console.WriteLine(name + " is " +? age + " years old.");


int c = System.Console.Read(); //Read single char
System.Console.WriteLine(c); //Prints 65 if user enters "A"
?
?
File I/O
?
VB.NET

?

Imports System.IO


'Write out to text file
Dim writer As StreamWriter = File.CreateText
? ("c:myfile.txt")
writer.WriteLine("Out to file.")
writer.Close()


'Read all lines from text file
Dim reader As StreamReader = File.OpenText
? ("c:myfile.txt")
Dim line As String = reader.ReadLine()
While Not line Is Nothing
? Console.WriteLine(line)
? line = reader.ReadLine()
End While
reader.Close()


'Write out to binary file
Dim str As String = "Text data"
Dim num As Integer = 123
Dim binWriter As New BinaryWriter(File.OpenWrite
? ("c:myfile.dat"))
binWriter.Write(str)
binWriter.Write(num)
binWriter.Close()


'Read from binary file
Dim binReader As New BinaryReader(File.OpenRead
? ("c:myfile.dat"))
str = binReader.ReadString()
num = binReader.ReadInt32()
binReader.Close()
?
?C#

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